Compressor blade for a gas turbine engine

ABSTRACT

A composite clappered compressor blade for a gas turbine engine comprising a plurality of individually forged pieces bonded together by electron beam welding or other metallurgical techniques to form the completed blade structure. The mated surfaces of the joint between the individually forged major pieces of the composite blade structure extend transversely across the longitudinal composite blade structure, the surfaces being easily machined to match accurately before bonding together.

United States Patent James A. Petrie; John M. S. Keen; Gordon C. May; Albert James Moreton; Frank Littlelord, all of [72] Inventors Derby, England v [211 App]. No. 15,561 [22] Filed Mar. 2, 1970 T23] Continuation-impart of Ser. No. 636,979,

May 8, 1967, Pat. No. 3,524,712 [45] Patented Oct. 5, 1971 w w- [73] Assignee Rolls-Royce Limited Derby, England [54] COMPRESSOR BLADE FOR A GAS TURBINE ENGINE 3 Claims, 4 Drawing Figs.

[52] 11.8. C1 416/190, 4l6/l93,4l6/196 [51] Int. Cl F0ld 5/10, F0ld 5/22 [50] Field of Search 416/190,

[56] References Cited UNITED STATES PATENTS 1,263,473 4/1918 Schellens 416/193 X 1,544,318 6/1925 I-Iodgkinson 416/196 X 1,670,558 5/1928 White 416/193 X 3,307,775 3/1967 Petrie 416/196 3,396,905 8/1968 Johnson 416/191 X FOREIGN PATENTS 189,131 3/1923 Great Britain 416/196 Primary Examiner-Everette A. Powell, Jr. Attorney-Cushman, Darby & Cushman ABSTRACT: A composite clappered compressor blade for a gas turbine engine comprising a plurality of individually forged pieces bonded together by electron beam welding or other metallurgical techniques to form the completed blade structure. The mated surfaces of the joint between the individually forged major pieces of the composite blade structure extend transversely across the longitudinal composite blade structure, the surfaces being easily machined to match accurately before bonding togetherv COMPRESSOR BLADE FOR A GAS TURBINE ENGINE This application is a continuation-in-part application of our copending US. application Ser. No. 636,979, filed May 8, I967, now US. Pat. No. 3,524,712 issued Aug. 18, I970.

The present invention relates to a composite compressor blade for a gas turbine engine and, more particularly, to such a blade having a clapper thereon.

Throughout the specification, the term clapper is to be taken to mean a lateral projection formed with one or more portions and extending from the blades working surface at a position situated between the longitudinal extremities of the working surface. The clapper" is arranged to abut with a clapper" on the next adjacent blade when the blades are assembled into a blade row of a rotor or a stator.

PRIOR ART Clappered blades for compressors of gas turbine engines have been heretofore manufactured from'a single piece of material by utilizing conventional forging techniques. With the advancement of gas turbine engine technology, the size of gas turbine engines has increased, causing a corresponding increase in size of the various parts thereof, including the individual compressor blades. To produce clappered compressor blades of increased size, from a single piece of material, required the development of special forging techniques. This technique has not been entirely satisfactory to the industry as it has resulted in high manufacturing costs of the clappered blades because of the complexity of and cost of operation of such forging equipment.

More recently, efforts have been made by the industry to develop other techniques for producing clappered blades, these techniques involving manufacturing of blades from a plurality of parts. These later techniques still resulted in the production of a costly blade and/or a blade which did not have sufficient strength for use as a clappered blade. Some of these latter mentioned techniques involved production of a composite blade having one section made from a forged or rolled piece of material, with the other section joined thereto, made from a section of suitable sheet material. Additionally, efforts were made in thepast to make composite blades for the turbine section of the engine with different sections made from different materials capable of withstanding difierent temperatures. Such blades were made from cast pieces, rather than forged pieces and were not used in a clappered blade construction.

Prior art patents disclosing various types of blades for gas turbine engines and techniques for manufacturing the same, are as follows: I

1,544,318-Hodgkinson June,l925

l,998,393-Junggren Apr.,l935

2,463,340-Wiberg" March, 1949 3,216,669-Schoenborn Nov., 1965 3,394,9l8-Wiseman July, 1968 3,396,905:-Johnson Aug., 1968 British 574,440-Sulzer Jan., 1946 British 660,007-Bolsezian Oct., 1951 British 680,0l4-Kent Oct, 1952 Swiss 246,346-Wyss Sept., 1947 SUMMARY OF THE INVENTION According to the present invention, a composite clappered compressor blade for a gas turbine engine comprises a first individually forged bladelike working section having a root portion integral therewith and extending outwardly therefrom on one extremity of the same and a portion of the clapper on the other end of the same, and a second individually forged bladelike working section having one end defining a tip and the other end having another portion of the clapper. The two individually forged bladelike sections had their ends with the clapper portion thereon machined and metallurgically joined in mating relationship with the joint so formed being intermediate of the clapper and extending transversely of the composite blades longitudinal axis. By providing the joint transverse of the longitudinal axis of the blade and intermediate the clapper, the machined surfaces for the metallurgical joint of the same are larger than if such surfaces had been made on a transverse cross section of a working section of the blade, thus providing a stronger overall blade construction. Additionally, the individually forged sections are easier to make as a total clapper does not have to be formed on one section or the other and, thus, conventional forging techniques are used.

The individually forged section of the blade having the tip may be hollow and ribs may be used internally to strengthen the same. Material for the blades of the present invention may be steel or titanium.

BRIEF DESCRIPTION OF THE DRAWINGS The invention to be subsequently described in detail is better understood by reference to the claims and accompanying drawings in which;

FIG. 1 is a diagrammatic elevational view partially broken away and illustrating a gas turbine engine incorporating compressor blades according to the present invention;

FIG. 2 is a side elevational view of the composite compressor blade of the present invention;

FIG. 3 is an enlarged fragmentary view of a portion of the blade of FIG. 2, the view illustrating the joint, and

FIG. 4 is a sectional view taken substantially on the line 4-4 of FIG. 3, the view being slightly enlarged over the view 0 FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings wherein like character or reference numerals represent like or similar parts, and in particular to FIG. I, there is disclosed a gas turbine engine I0 having a compressor 11, a combustion section 12, a turbine section 13, and a final nozzle 14, all of which are in flow series. The compressor 11, which is more visible due to the breaking away of the casing, comprises stator blades 15 and rotor blades 16. While the composite blade of the present invention will be described in connection with the rotor blades 16, it will be appreciated by those skilled in the art that the invention could be equally well applied to the stator blades 15, if it is desired to provide such stator blades with clappers. Normally stator blades do not require clappers but if a more rigid stator is desired, the blades of the same may be provided with clappers.

In FIG. 2 of the drawings, there is illustrated a composite clappered rotor blade 16 of the present invention, the blade 16 being formed of individually forged working sections 25 and 26, respectively, made from a suitable material such as titanium or steel. Each of the working sections 25 and 26 is of the usual aerofoil shape in cross section, so that one side of the blade is convex and the other side is concave. The composite clappered blade 16 includes a root portion 27, a clapper generally designated at 32 and a tip portion 33. The working section 25 is joined to the working section 26, along a metallurgical joint 34 intermediate of the clapper 32 and extending in a plane transversely of the longitudinal axis of the blade 16. The joint 34 is made by an electron beam weld or by some other metallurgical bond, such as a diffusion bond.

The individually forged section 25 is the inner section of the composite blade I6 and is provided with working surfaces 28. The root portion 27 is an integral part of the working section 25 and it extends outwardly from one extremity thereof. At the other extremity of the working section 25 is a platform portion 29 which forms part of the clapper 32, the platform portion 29 projecting laterally from both sides of the working section 25. Additionally, the platform portion 29 has a machined surface 35, which lies in a plane transverse of the longitudinal axis of the section 25.

The individually forged working section 26 is the outer working section of the composite blade 16 and it has working surfaces 30 and a platform portion 31 at one end thereof which also forms part of the clapper 32 of the composite blade. The other end of the working section 26 defines the tip portion 33 of the blade. The platform portion 31, which forms part of the clapper 32, projects laterally from each side of the working section 26 and is provided with a machined surface 37 which is adapted to mate with the machined surface 35.

When the composite blade 16 is formed, the mating machined surfaces 35 and 37 are abutted together and joined as an integral unit by electron beam welding, or some other form of metallurgical bonding, such as diffusion bonding. The platform portions 29 and 31, which form the clapper 32, thus define a clapper wherein there are at least two projecting portions from each side of the composite blade 16, the two projecting portions being arranged to abut two like portions on an adjacent blade when the blades 16 are assembled into a blade row of a rotor. By having the joint 34 intermediate the clapper 32, the machines surfaces 35 and 37, which fit together accurately, define a larger surface at the point of the metallurgical joint 34, and thus provide a stronger overall blade construction.

While the outer working section 26 has been shown as solid, it will be appreciated that this section, having the tip portion 33, could be made hollow, if desired, thus resulting in a lighter composite blade structure.

It will be seen that the present invention provides a large clappered blade which can be made without the necessity of forging the whole blade and clapper from a single piece of material, as this would be difficult, both because of the large size of the blade and because of the fact that the clapper extends or projects laterally from the major axis of the blade. The main surfaces of the individually forged sections of the composite blade of the present invention are each formed on a portion of the clapper, and, thus are not complex in shape but are relatively large surface area, as compared to a cross section through the working surface. This results in a larger beam welded joint and a composite blade which is stronger in its joined area.

The terminology used throughout the specification is for the purpose of description, and not limitation, the scope of the invention being defined by the claims.

We claim:

1. A composite compressor blade comprising:

' a first individually forged bladelike working section having a root portion integral therewith and extending outwardly from one end thereof and a platform portion integral therewith and extending laterally from both sides thereof at the other end, said platform portion having a machined surface transverse of the longitudinal axis of the first section;

a second individually forged bladelike working section having a tip portion at one end and a platform portion integral therewith and extending laterally from both sides at the other end, said platform portion of said second section having a machined surface transverse of the second section which mates with said machined surface of said first section;

a metallurgical joint between said mating machined surfaces of said platform portions of said first and second sections, said metallurgical joint having a transverse cross-sectional area greater than transverse crosssectional area of either of said first and second working sections; and

a clapper formed by said platform portions of said first and second sections and said joint, said clapper having a pair of closely spaced projections defined by said platform portions of said first and second sections extending laterally from each side of the blade.

2. A composite compressor blade comprising:

a first working section having a root portion;

a second working section having a tip portion;

a clapper extending laterally from each side of the blade intermediate said first and second section, said clapper being formed from two pieces joined by a metallurgical joint lying in a plane transverse of the blade, said two pieces having their free ends defined by close longltudinally spaced projections, one piece of said clapper being integral with said first working section, and the other piece of said clapper being integral with said second working section.

3. A composite compressor blade as claimed in claim 2, in which said first working section and its integral piece of said clapper is individually forged and in which said second working section and its integral piece of said clapper is individually forged.

UNKTED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 36 377 Dated October 5, 1971 Petrie, James A., Keen, John M. 3., May, Gordon 0. Moreton, Albert J., and Littleford, Frank Patent No.

Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

, In the above identified patent, please add the following to the front page format;

[32] Priority May 17, 1966 [33] Great Britain Signed and sealed this 29th day or February 1972.

(SEAL) Attest:

EDWARD M.FLETCHEH, JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PC4-1050 (10-69) 

1. A composite compressor blade comprising: a first individually forged bladelike working section having a root portion integral therewith and extending outwardly from one end thereof and a platform portion integral therewith and extending laterally from both sides thereof at the other end, said platform portion having a machined surface transverse of the longitudinal axis of the first section; Pg,12 a second individually forged bladelike working section having a tip portion at one end and a platform portion integral therewith and extending laterally from both sides at the other end, said platform portion of said second section having a machined surface transverse of the second section which mates with said machined surface of said first section; a metallurgical joint between said mating machined surfaces of said platform portions of said first and second sections, said metallurgical joint having a transverse cross-sectional area greater than transverse cross-sectional area of either of said first and second working sections; and a clapper formed by said platform portions of said first and second sections and said joint, said clapper having a pair of closely spaced projections defined by said platform portions of said first and second sections extending laterally from each side of the blade.
 2. A composite compressor blade comprising: a first working section having a root portion; a second working section having a tip portion; a clapper extending laterally from each side of the blade intermediate said first and second section, said clapper being formed from two pieces joined by a metallurgical joint lying in a plane transverse of the blade, said two pieces having their free ends defined by close longitudinally spaced projections, one piece of said clapper being integral with said first working section, and the other piece of said clapper being integral with said second working section.
 3. A composite compressor blade as claimed in claim 2, in which said first working section and its integral piece of said clapper is individually forged and in which said second working section and its integral piece of said clapper is individually forged. 